Invoice Total Calculator
Calculate invoice totals from line items, quantity, and unit price.
Apply tax and discount to get itemized subtotal, tax, and final balance for billing.
An invoice total is calculated by combining line item subtotals, applying discounts, and then adding applicable taxes. The standard invoice calculation formula is:
Invoice Total = (Σ Line Items) − Discount + Tax
Step by step:
Line Item Total = Quantity × Unit Price
Subtotal = Σ All Line Item Totals
Discount Amount = Subtotal × Discount Rate (if percentage) OR fixed amount
Taxable Amount = Subtotal − Discount Amount
Tax Amount = Taxable Amount × Tax Rate
Invoice Total = Taxable Amount + Tax Amount
Worked Example — Freelance web design invoice:
| Item | Qty | Unit Price | Line Total |
|---|---|---|---|
| Logo design | 1 | $350.00 | $350.00 |
| Homepage design | 1 | $600.00 | $600.00 |
| Revision rounds | 3 | $75.00 | $225.00 |
- Subtotal = $1,175.00
- Loyalty discount (10%): −$117.50
- Taxable amount = $1,057.50
- Sales tax (8.5%): +$89.89
- Invoice Total = $1,147.39
Early Payment Discount (common in B2B): “2/10 Net 30” means 2% off if paid within 10 days, full amount due in 30 days. $1,147.39 × 0.98 = $1,124.44 if paid within 10 days
Reference: US small businesses write off ~$300 billion in bad debt annually. Net 30 terms are standard; Net 60/90 are common in construction and government contracting. Always include payment terms, late fees, and accepted payment methods on every invoice.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.